Measurements Using An External Voltmeter; Set Up; Procedure - Agilent Technologies HP E1355A User Manual

Poisson Full Bridge
(FPOisson)

Measurements Using an External Voltmeter

Set Up

Procedure

Chapter 4
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In applications where the specimen is stressed lengthwise, the measurement
sensitivity is increased and temperature compensation is achieved when the
gages are mounted to the specimen as indicated in Figure 4-16.
Figure 4-16. Poisson Arrangement
This section describes how measurements are made using a strain gage
multiplexer switchbox and a voltmeter external to the HP 75000 Series B or
Series C mainframe.
When making strain measurements with an external voltmeter, the strain
gage multiplexer is configured for
described in Chapters 1 and 2.
The external voltmeter is connected to the multiplexer through the HI, LO,
and G terminals on the multiplexer terminal module (Figures 2-7, 2-8).
Measuring strain with an external voltmeter involves measuring the
Wheatstone bridge output voltage (Vout) and the bridge excitation voltage
(Vs) under strained and unstrained conditions. These measurements allow
you to compute the value of Vr, which in equation form is defined as:
Vr = [(Vout/Vs)strained - (Vout/Vs)unstrained]
Vr is then substituted into the appropriate equation (Table 4-1 on
based on the bridge arrangement used.
Examples of strain measurements using the relay and FET multiplexers and
an external voltmeter are contained in Chapter 3.
Understanding the Strain Gage Multiplexers
⁄ ⁄
1 , 1 , and full bridge measurements as
4 2
page 52)
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